so I'm starting to get scared and not sure what to think...

On the 26th of August, a couple days after my actual Ovulation day my boyfriend and I had anal sex. He absolutely loves it and I just kinda put up with it lol. Anyways he begged to 'let go' in my bum so I said yea that's fine. So he did so, and then he pulled out. Before he pulled out he had his hand ready and 'caught' the sperm that leaked out of me. He then took a towel and cleaned me up. What if he missed some of some seeped through his hand and went in my vagina? What are the actual chances of that happening?? My period is supposed to be in 3 days and yesterday and the day before I had light spotting. My boobs hurt on the sides like they always do before my period but I'm just scared I still could be pregnant.